progress: set default delay threshold to 100%, not 0%

progress: set default delay threshold to 100%, not 0%

Commit 8aade107dd (progress: simplify "delayed" progress
API, 2017-08-19) dropped the parameter by which callers
could say "show my progress only if I haven't passed M%
progress after N seconds". The intent was to just show
nothing for 2 seconds, and then always progress after that.

But we flipped the logic in the wrapper: it sets M=0,
meaning that we'd almost _never_ show progress after 2
seconds, since we'd generally have made some progress. This
should have been 100%, not 0%.

We were fooled by existing calls like:

  start_progress_delay("foo", 0, 0, 2);

which behaved this way. The trick is that the first "0"
there is "how many items total", and there zero means "we
don't know". And without knowing that, we cannot compute a
completed percent at all, and we ignored the threshold
parameter entirely! Modeling our wrapper after that broke
callers which pass a non-zero value for "total".

We can switch to the intended behavior by using "100" in the
wrapper call.

Reported-by: Lars Schneider <larsxschneider@gmail.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>